Important is the <scope>source.rainmeter</scope> that defines that you are in a Rainmeter file,<tabTrigger>trotator</tabTrigger> is the command you want to define for that snippet to activate and content is obviously the content.$2 for example are tab markers, thus $2 would be the position after tabbing once.

I played around a bit with the homepage https://thatsich.github.io/sublime-rainmeter/.
I tried using some stuff which is more fancy than the content it provided (content was like 4 years old).
I am not a frontend developer so if you have suggestions to improve the UX, feel free to open an issue.

eclectic-tech wrote:You can access the snippets in 2 ways:
1. Type 't' in the document, to show a popup list of template snippets for meters and measures.
2. Select 'Tools' menu and 'Snippets...' for a window list.

Thanks eclectictech - the power of the extremely obvious somehow skips me every time